Process of making dies or patterns for metal-working



UNITED STATES.

PATENT OFFICE.

CHARLES F. HIRONS, OF MEDFORD, MASSACHUSETTS.

PROCESS OF MAKING DIES OR PATTERNS FOR METAL-WORKING.

SPECIFICATION forming part of Letters Patent No. 497,982, dated May 23, 1893.

Application filed July 23, 1892. Renewed April 17, 1893. Serial No. 470,763. (No specimens-l To all whom it may concern:

Be it known that I, OHARLEs FREDERICK HIBONS, a citizen of Great Britain, residing at Medford, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Dies or Patterns for Metal-VVorking, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention has for its object to provide a die or pattern by means of which designs, letters and the like may be produced on metal rapidly and inexpensivelyand'it consists more particularly in the method hereinafter set forth and which is pointed out in the claim of producing such a die or pattern.

My invention will be readily understood from the following description of the way in which a die or pattern constructed in accordance therewith is made. I take a piece of steel of the desired size and thickness having a substantially smooth face and subject the face to be used to the action of acid, preferably sulphuric, to clean it from scale. The action of the acid renders the surface more or less open and porous and to close the pores terials may be employed but I prefer the substances named. Asketch of the design which I desire to reproduce is then cut on the coating of clay, glue or varnish, the lines passing through the coating, so as to expose the steel beneath. I then subject the steel thus prepared to the action of acid which will not affeet the clay, glue or varnish but will attack the steel where it is uncovered. This acid treatment is continued until the background of steel is eaten away to the depth which may be desired, after which the plate or block is treated with a strong solution of nitric acid in water. This latter treatmentalthough not indispensible is very desirable as it has the effect of sharpening the lines of the design and making it clear and distinct thereby improving the impression obtained. The surfaceof the steel is then brushed over to thoroughly clean it and the die or pattern is ready to be used in the reproduction of the design on brass or any other metal. In obtaining a reproduction of the design on metal, the metal upon which the design is to be reproduced is placed in contact with the face of the die or pattern and subjected to a strong pressure. The pattern or die so made is durable and may be used to produce an indefinite number of reproductions.

What I claim is- The method herein described of making a steel die, or pattern for metal working consisting in first cleaning the surface of the steel by treatment with acid, then subjecting the said surface to pressure to densify the same, then covering the surface with an acidresisting material, then reproducing the design in the said acid-resisting covering so as to expose the face of the steel behind the outlines thereof, then subjecting the plate or block so prepared to the action of acid whereby the surface of the exposed portions of the steel are attacked and eaten away, substantially as set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

CHARLES F. HIRONS.

IVitnesses:

WM. A. MAoLEon, R. WALLACE. 

